Freezer liner and method of making same



Jan. 14,1958 H. SMITH 2,819,593

FREEZER LINER AND METHOD OF MAKING SAME Filed Sept. 9, 1953 2 Sheets-Sheet l 1A Egg-1 f I I Q II 1 g i m I" & L

' Harold 5122ZZ7L Jan. 14, 1958 H. SMITH 2,819,593

FREEZER LINER AND METHOD OF MAKING SAME Filed Sept. 9, 1953 2 Sheets-Sheet 2 ZnFE IZZLU 1 Ham/0 5221M United St Refrigeration, Ind, Arnana, Iowa, a corporation of Iowa Application September 9, 1953, Serial No. 379,155

3 Claims. (Cl. 62-426) The present invention relates to liner assemblies for use in chest type food freezers. More particularly, the invention relates to a novel construction of a stepped type food compartment for use in. such freezers or the like.

It is common practice in the refrigeration industry to provide chest type food freezer units with a pair of compartments one of greater depth than the other. These compartments have, in the past, been entirely separate units thus requiring, in effect, a double thickness. Wall between the two compartments. This type of construction has rendered the freezer unduly expensive, much more diflicult to manufacture, less rigid than desired and also relatively unhandy in instances in which odd sized packages are desired to be frozen.

It has, of course, been long recognized that a liner having a deep portion and a relativelyshallow portion is desirable since the refrigeration compressor and motor are preferably located in the base of thefreezer cabinet under the shallow portion of the liner. Further, in. some instances, the householder desires the use of smaller shallow compartment for quick-freezing and for the storage of items intended to be used rapidly, thereby positioning them within eachy reach and not requiring the constant reshuffiing of frozen food packages deep down within the main freezerchamber. While these advantages may of course to a certain extent. be achieved through. the prior art structures, nevertheless the above mentioned disadvantages resulting from the prior art structures have adversely afiected both the cost-and the quality of the prior art structures and the need for the novel unitized structure herein disclosed and claimed has therefore long existed.

In overcoming the prior art. limitations, applicant has provided a substantially unitized freezer compartment providing a stepped, one-piece, bottomasurface and simply constructed side wall surfaces requiring no deepdrawing. These portions are sealed together to form a rigid one-piece structure in place of the prior art separate compartments. By providing this single piece, all cross bracing between the former two compartments is eliminated while at the same time retaining rigidity of the individual compartments. Further, no gasket material is required to cross the top or open portion ofthe liner unit to seal the separating walls of the compartments as was required in prior art structures, thereby eliminating a ditiicult sealing problem.

Further, by providing a un'itized structure applicant is enabled conveniently to utilize coil winding. apparatus for completely wrapping the stepped liner with tubing which forms the evaporator of the refrigeration system. Also, the unitization of the liner unit permits the placement of a portion of the evaporator coil tubing across the bottom surface of the smaller or upper step of the compartment thereby positively assuring the. elimination atent' O i ofundesired heat arising from the compressor and motor 2,81 Patented Jan. 14, 1958 2 structure and increasing the rate of removal of heat from the food placed on the upper step ofsthe liner unit.

Thus, throughthe above mentioned elimination of the dual compartment liner structure and the provision of suitable partitions, applicant has been able to provide a far simpler and .yet much superior liner structure .for use in freezer assemblies. It is therefore an. object of the present invention toprovide a liner compartment having a stepped bottom forming a single stepped com- 'partment.

Another object .of the present invention is to provide a novel one. piece, stepped, bottom plate for a refrigerator compartment liner and a novel method for manufacturing the same.

Still another object of the present invention is to provide a simplified one piece freezer compartment pro viding a maximum in rigidity with a minimum of cost.

Another. object of the present invention is to provide a one-piece step-bottomed liner compartment having cooling coils in contactwith the bottom of the upper step of the compartment.

Another object of the present invention is provision of a step-bottomed liner compartment having a single evaporator tube coiled completely around the entire compartment at points located above the upper step of the compartment, and. having a coil in contact with the upper step of the compartment and a further coil wrapped around the portion or" the compartment comprising the lower step.

A feature of the present invention is a method of construction which requires no deep draws of sheet metal whatever, whileat the same time providing an absolutely seamlessliner bottom.

Still. .otherand further features of the invention will become apparent tothose skilled in the art on consideration of the. attachedsheetsofdrawings in which. a preferred embodiment ofthe present invention is shown.

Headings on the drawings:

Figure l is a side elevational view showing an assembled. freezer liner constructed according to the present invention.

Figure 2 is an. end elevational view and partial cross section taken along the line llwilaof Figure 1.

Figure 3 is a partial bottom view of the liner showing applicanfis novel evaporator coil arrangement.

Figure 4 is a cross sectional view of the side Wall seam taken along line'IV-lV of Figure 1.

Figure 5 is a side .elevational view of the initial stamping from which the bottom plate or pan of the liner is constructed.

Figure 6 is a view of the bottom pan after a second operation and immediately prior to bending it to the form shown in the assembly of Figure 1.

As' shown on the drawings:

As may be seen from a consideration otFigures 1 and 2 a freezer liner unit generally indicated at liti is provided within an outer chest: type freezer cabinet, the outlineof which is showu generally by the dotted lines indicated at 11. At the dotted lines shown at 12, a compartment containing compressor units of conventional design, not shown, is placed. Between the outer compartment, indicated at 1l,the compressor indicated at 12 and the inner liner it), insulating material also not shown, is provided for preventing the transfer of heat from the inside of the liner It to the outside of the freezer cabinet or from the compressor compartment to the liner 10. p

The liner constructed according to the invention comprisesra one-piece base pan generally indicated at 13 and having awbottom: step surface 14, a vertical wall 15 and amupperistepr surface 16. The bottom pan. 13 is flange 18 of the wall surface 15.

constructed of a single piece of sheet material as will be described below and is provided with an upstanding peripheral flange 17 associated with the bottom step surface 14, 18 associated with the wall 15, and 19 associated with the upper stepped surface 16. The upstanding peripheral flanges 17, 18 and 19 are provided with deflected support ridges 20, 21 and 22 respectively as may be seen from Figures 1 and 2.

In order to provide a simple unified liner structure, a pair of sheet metal portions, formed in the shape of a U by a simple bending operation, are placed in butting relationship and secured at their bottom edges to the bottom plate 13. Thus, as may be seen from a consideration of Figures 1 and 2, a U-shaped deep liner member generally indicated at 25 and having an end wall or bight portion 26 and side walls 27 and 28 is secured. preferably by spot welding, to the upstanding peripheral flange 17 of the bottom surface 14, and to the upstanding Similarly, a U-shaped shallow liner generally indicated at 30 is provided having an end wall or bight portion 31 and side walls 32 and 33.

Each of the walls 31, 32 and 33 is preferably secured to the peripheral flange 19 of the upper step 16 by spot welding in the manner indicated relative to the deep liner 25. An overlapping joint, generally indicated at 34 is provided between the liners 25 and 30 as may be more clearly seen from Figures 2 and 4. This joint is likewise preferably jointed, as for example by spot welding, at intervals along the seam.

The result of the above described construction is a unitized step-bottomed liner having extreme rigidity. As will be noted, the bottom surface is provided by a one piece, dual-level pan which is secured at both levels to U-shaped sheet metal members. Due to the rigidity of the seam 34, and due to the fact that the U-shaped liner 25 is rigidly secured both along its bottom edge to the flange 17 and along one side edge to the wall flange 13, the entire assembly is maintained rigidly against buckling in any direction. Thus, the U-shaped shallow liner 30 is rendered immobile and may not shift or change its position relative to any portion of the structure. Through this unique construction, therefore the deep portion 25 of the liner and the shallow portion 30 of the liner are positively and securely fixed to each other and no shifting whatever may take place between the levels of the liner bottom 13 relative to other portions of the liner itself or to the outer cabinet.

A supporting strip 35 is spot welded across the upper marginal portions of the U members 25 and 26 to provide "reater rigidity and also to cooperate with retaining means for rigidly securing the liner to the outer cabinet 11. Such retaining means do not, however, form a part of the present invention and are not shown.

After the liner has been assembled to the extent above described, the entire liner 1G is wound with a coil of copper tubing 36 on a Winding machine or other conventional apparatus for this purpose. The coil is maintained in position securely against the sides and end walls of the liner 25 by a plurality of strips 37 which are spot welded, as for example at 38, to the respective liner members. The strips 37 have deformed loops 3? providing clearance for the tubes 36 while at the same time maintaining the tubes firmly against the liner exterior surface.

As may be readily seen from a consideration of Figures 1 and 3, provision is made for securing a loop of the evaporator coil 36 securely against the surface 16 of the upper step of the bottom plate 13. This securing means comprises a pair of arcuately formed retainer clips 44) having out-turned retaining flanges 41. The securing members 40 may be positively aflixed to the surface 16 by spot welding as at 42, or any other conventional means. The ends 43 and 44 of the tubing 36 lead to the remainder of the refrigerating system, namely the 4. condenser and the compressor, which portions form no part of this invention.

After the above outlined steps have been completed, a thermally conductive adhesive material is applied around the evaporator tubes 36 to maintain them in high efiiciency thermal contact with the walls of the liners 25 and 30 respectively. A plastic sealing material may also be inserted at the joint 34 if so desired in order to smooth out the joint internally and to provide a completely air tight seal. After these steps have been taken the entire outside surface of the unit may be painted if desired and the internal surface of the liner may likewise be given its final finish.

An important feature of the present invention is the novel construction of the step bottom pan 13. As may be seen from Figures 5 and 6, this pan is constructed from a single, shallow drawn, stamped pan which is formed in the Z shape seen in Figure 1. 1n the initial step of production, the pan is drawn from a fiat sheet of sheet metal material into a shallow pan having the upstanding flanges 17 and the support ridge 20, as shown in Figure 5. After this step, the pan is mitered at 0pposite sides at a substantially angle as shown at 455 and is provided with ground, round notches 46. Subsequently, the pan is bent at 47 until the mitered edges 45 butt each other as shown in Figure 1. This butting joint is then preferably welded to provide a completely rigid construction.

Either simultaneously with the above described miter operation, or independently thereof, the Walls of the pan adjacent the notches 46 are heated and the surfaces 16 and 15 bent at 48 to a configuration shown in Figure 1. The notches as are provided to completely eliminate any possibility of tearing at the bend 48 and as may be seen from a consideration of Figure 1, the stretching of the metal changes the curved notches 46 into a substantially straight line surface as shown at 49 in Figure l. The unitized, one piece pan thus constructed from shallow drawn sheet metal material is utilized in the above described assembly and is, as above noted, spot welded along its periphery to securely form a unitized liner. As in the case of the joint 34, plastic sealing material is preferably utilized, along with the spot welding, to provide a completely air and water tight seal between pan portion 13 and the U-shaped deep and shallow liners 25 and 341 respectively.

From a consideration of the construction of the above described liner, it will be apparent that a deep well and a shallow well are provided. As described above, these wells are not separated by any wall and are maintained in stiff relationship with one another. However, in operation it may be desired that the deep and shallow wells be separated by a heat insulating material. In such a case a divider may be provided secured to the upper edge of the liner in the manner shown in the co-pending application of Robert E. Moore, Serial Number 314,622 filed October 1.0, 1952. In that application the provision of a wire type divider is shown, but it is, in the present instance considered desirable that the divider be constructed of a substantially solid insulating material to completely separate the shallow and the deep liners under certain refrigerating circumstances.

If, on the other hand, large pieces of meat or similar materials are desired to be maintained in a frozen con dition, the divider may be removed and the entire length of the unit made available for the holding of the long or otherwise ungainly shaped food.

It will thus be seen that I have provided a novel, com pact, and highly etficient as well as extremely inexpensive liner structure for use in chest type freezers or the like.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. A liner assembly for chest type freezer units com prising in combination, a one piece shallow stamped bottom pan having a stepped construction providing a lower horizontal step surface and an upper horizontal step surface, said step surfaces being joined by a substantially vertical step wall, a first U shaped wall section and a second U shaped wall section, the bights of said Us forming the end walls of said liner and the legs of said Us joining each other to form the side walls of said liner, the first of said Us having a greater depth than the second whereby it may be secured to the lower step and step wall to provide a deep chamber and to provide reinforcement for the second U.

2. A liner assembly for chest type freezer cabinets comprising a two depth liner compartment having an upwardly flanged one piece stepped bottom pan and a pair of abutting U shaped wall portions secured to said flange to provide a deep compartment portion and a shallow compartment portion, means for securing evaporator tubing in continuous coils about said wall portions and second means for securing at least one of said coils to the bottom pan under the shallow compartment portion as it passes around the deep portion.

3. The method of manufacturing a liner for chest type freezers which comprises forming a one piece stepped bottom plate having a vertical wall separating the steps,

bending a first sheet metal U, securing said U to the lower step and vertical wall of said plate so that the bight of the U lies in a plane opposite and parallel to the vertical wall of the stepped plate, bending a second U of sheet metal and securing said second U to the upper step so that the bight of said second U is opposite and parallel to that of said first U and so that the legs of said Us are in juxtaposition, and securing the adjacent edges of the legs of said Us to each other.

References Cited in the file of this patent UNITED STATES PATENTS Re. 21,997 Stanitz Jan. 6, 1942 1,879,241 Hill Sept. 27, 1932 2,023,154 Trotter Dec. 3, 1935 2,185,904 Stowe Jan. 2, 1940 2,226,670 Pratt et al Dec. 31, 1940 2,302,051 Philipp Nov. 17, 1942 2,418,152 Avery Apr. 1, 1943 2,423,863 Wales July 15, 1947 2,481,512 Hubbell Sept. 13, 1949 2,483,842 Philipp Oct. 4, 1949 2,497,734 Kuklich Feb. 14, 1950 2,677,250 Alsing May 4, 1954 

